Cocaine is the primary illicit drug used by pregnant omen and a growing public health concern because of the risks to the offspring. In the neonatal period, these include low birth weight and neurobehavioral abnormalities. There are to date, no systematic data on the neurodevelopment of children exposed in-utero to cocaine. We propose to evaluate the neurological outcome of neonates exposed to cocaine in-utero. The cohort will comprise about 300 infants, about 150 cocaine-exposed and 150 unexposed, recruited from a single NYC hospital over 2 years. Exposure status during pregnancy will be ascertained by chart abstraction for urine toxicology results, self report by interview, and/or maternal hair extract for cocaine metabolites. In addition, we use an existing data set, the Perinatal HIV Transmission Neurodevelopment Add-On study (PI, Dr. Maria Suarez), to analyze the effects of in-utero cocaine-exposure on neurodevelopment outcome in uninfected children. A first objective will be to determine the effect of intrauterine cocaine exposure on outcomes at birth: head size, gestational age, intrauterine growth, and neurological status. Data will be drawn from anthropometric measures, gestational assessments, neurological examinations, and chart abstraction. A second objective will be to determine whether in-utero cocaine exposure is associated with an increased risk of neurobehavioral impairment in children followed until age three. Contrasts between the two groups of infants (exposed and unexposed) will assess whether the risk for adverse outcome or impairment is specific to cocaine-exposed infants, or similar to that conveyed to infants of similar racial and socioeconomical status.